docs: def validiate_webhook_signature(self, webhook, signature):
          """Validates a webhook signature from a webhook body + client secret
  
          Parameters
              webhook (string)
                  The request body of the webhook.
              signature (string)
                  The webhook signature specified in X-Uber-Signature header.
          """
          digester = hmac.new(self.session.oauth2credential.client_secret,
                              webhook,
                              hashlib.sha256
                              )
          return (signature == digester.hexdigest())